Battery-operated riding mowers are known which have three wheels and reel-type blades in front of the vehicle. The reel blades rotate vertically in response to the forward motion of the mower. These mowers are useful mainly for mowing golf putting greens. Rotary blades are not suitable for these mowers because they would cause a lack of balance and be unstable. U.S. Pat. No. 4,145,864, issued to Brewster, discloses a battery-powered push rotary lawnmower. This lawnmower has a single motor, with a motor controller and potentiometer, which rotates a blade horizontally under the motor. The wheels are not powered by the motor. A battery-operated riding rotary lawnmower is desirable because it would operate cleaner, more dependably, and with less maintenance than a gasoline powered riding rotary lawnmower.
U.S. Pat. No. 7,578,116 discloses a battery-operated riding rotary lawnmower having batteries positioned in a U-shaped array around the right side, left side, and rear end of the chassis. The batteries are above and near the rear wheels to maintain a low center of gravity. The weight of the batteries is evenly distributed over the rear wheels to maintain balance. A single electric motor is positioned within a central portion of the U-shaped array of batteries and drives both the rotary cutting blades and the rear wheels. The use of a single motor in this system requires relatively complex electronics including a motor controller, a speed controller, a potentiometer, and a tachometer, in order to operate the cutting blades and drive transmissions independently. In some cases it may be desirable to simplify the system by using one motor to operate the cutting blade and one motor to operate the drive transmission. However, the use of two motors requires the riding mower to have an excessive length. What is needed is a two-motor system that will allow a compact battery-operated riding rotary mower.